cells and batteries

Question 1

criteria for material of electrodes

Answer 1

-must be a conductor of electricity
-should help in the catalysis of redox reaction if the latter is slow
-inertness to reaction inside the cell
-porous in fuel cells using gaseous reactants- provide surface area for electrolysis

Question 2

alkaline Zn/MnO2 cell

Answer 2

anode: Zn(s) + 2OH- -> Zn(OH)2(s) + 2e-

cathode: 2MnO2(s) + 2H2O(l) + Zn(s) -> 2MnO(OH)(s) + Zn(OH)(s)

Question 3

factors affecting battery life

Answer 3

-loss of active materials (reactants and products of the cell reaction). May be converted to inactive forms by side reactions
- formation of other chemicals in side reactions that impede the efficient functioning of the cell

Question 4

rate of deterioration of a battery

Answer 4

depends on temperature: higher temperature = faster deterioration + increase in rate of side reactions